Electric furnace



Aug. 14, 1923. 1.464.543

M. SAUVAGEON ELECTRIC FURNACE Filed pril 2 1921 4 Sheets-Sheet 1 .71, van fir:

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M. SAUVAGEON ELECTRIC FURNACE Filed April 2,

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Aug. 14, 1923. 1,464.543

M. SAUVAGEON ELEGTRI C FURNAC E Filed April 2, 1921 4 Sheets-Sheet 4 Fig. I

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Patented Aug. 14, 1923.

UNITED STATES MUS SAUVAGEON, OF PARIS, FRANCE.

ELECTRIC FURNACE.

Application filed April 2, 1921. Serial No. 468,018.

To all wlwm it may concern:

Be it known that I, Marius SAUVAGEON, a citizen of the French Re ublic, residing at No. 7 Rue de Petrograd, saris, France, have invented certain new and useful Improvements Relating to Electric Furnaces (for which I have filed a plications in France August 3, 1916; Cana a, June 6, 1919; Italy, May 2, 1919), of which the following is a specification.

This invention relates to an electric resistance furnace heating by radiation either from the crown alone, from the sides alone or simultaneously from the crown and from the sides. The heat is produced by the passage of current through an electirc resistance formed partly by material in grains having a basis of carbon placed in chambers disposed one beside the other above the crown of the furnace or in the walls thereof and partl by the crown and the walls themselves whic are constructed of special material being good conductors of heat and becoming electric conductors at high temperature. The heating chambers in which is placed the resistance material in the form of grains have openings at their upper ends in such manner as to permit the inspection of the chambers and especially to assure the automatic replacement of the granular resistance material which is used so as to maintain always the same conditions in the a paratus in assuring a constant section 0 the resistance material and thus the permanence of the conditions of working, that is to say the automaltic feed of the granular resistance materia This mode of heating by radiation may be applied to various industrial furnaces adapted for the fusion, heating or baking of substances and at any temperature from the lowest such as required in stoves to the highest such as is necessary in the manufacture of steel, of glass and ceramic products. In each case the laboratory or bed of the furnace will be provided of a form and'dimensions according to the manufacture to be carried on.

The accompanying drawin define the object of the invention and in icatc by way of example three modes of construction of furnace.

Figure 1 is a transverse section of a furof materials placed directly upon the hearth.

Figure 2 is a longitudinal section of the furnace represented in Figure 1 one part of which is made through the feeding pockets and the other between the feeding pockets.

Figure 3 is a transverse section of a furnace similar to that indicated in Figures 1 and 2 but with the crown and electric hearth suspended and an independent bed provided especially for fusion of products at high tem rature such as steel and glass.

Figure 4 is a longitudinal section of the furnace represented in Figure 3, the section being taken partly through the feeding pockets and partly between the pockets.

Figure 5 is a transverse section of a furnace simultaneously heating from the crown and walls with vertical electrodes placed beneath destined to heat the solid or melted substances contained in the receptacle.

Figure 6 is a longitudinal section of the furnace represented in Figure 5, the section being taken partly through the axis of the furnace and partly through the electrodes.

Figures 7 and 8 show respectively in longitudinal section and horizontal section a modification permitting the application to the case of a furnace having an oscillating crucible of heating chambers with an automatic feed.

The furnace represented in Figures 1 and 2 comprises a laboratory 1, a bed 2, walls 3, a crown 4 and a working hole 5 closed by a door 6. The mode of construction of the bottom and walls as well as the position and number of the working holes are provided in each case according to the heating operation to be carried out and the nature of the products to be treated.

The crown 4 and the walls of the electric hearths are made of very refractory material constituted by ferrite of magnesia and ferrite of alumina containing from 5 to 10 per cent of oxide of iron agglomerated in a ress and heated to a high temperature. base materials have the protperty of being good conductors of heat an of becoming good conductors of electricity at hi h temperatures and have a high physica resistance. The construction of the setting is effected in the usual manner by the employment of bricks or of blocks of convenient form and a grouting of the same substance as the bricks or looks is employed for the o1nts.

Above the crown are disposed a series of heating chambers 7 having a length extending across the crown and separated one from the other by partitions 8. They are closed at their upper parts by a top in which are provided several openings 9 having the form of pockets widening out downwardly. These openings are closed normally by cover plates 10. At the two opposed extremities of each chamber electrodes 11 are provided connected by the conductors 12 to the leads 13. These electrodes are placed horizontally or vertically and the chambers can be disposed either parallel or in series or in series and parallel. Further the heating chambers can extend either across the furnace or longitudinally of the furnace.

The furnace is braced as usual as for example in the manner illustrated by means of bars, braces and bolts. In each chamber there is charged an electric conductive substance in the form of grains. For [ills purpose natural or artificial graphites may be employed retort carbon. coke and the like. The size of the grains as well as the section of each chamber may be determined according to the nature of the operation to be performed. The resistance material fills each chamber as well as the feeding pockets 9 as indicated in the drawing. It follows that if part of the substance burns it is replaced automatically by the excess contained in the feeding pockets and thus the section of the resistance material remains always the same. As before indicated there is obtained by this means a furnace which has practically a constant working. Moreover each chamber can be inspected and cleared easily even in working through the l'eedin pockets.

The furnace re resented in Figures 3 and 4 is similar to t e furnace previously described with respect to the disposition of the heating crown and the electric hearth; but the whole is entirely suspended and separated from the hearth. The latter disposed beneath is constituted by a basin destined to receive the substance to be treated. The space comprised between the suspended crown and the basin forms the laboratory 1 which is closed by the bricks placed upon the grouting at the edges of the basin.

The apparatus thus comprises essentially a lower structure constituted by a basin 2' resting u on a series of partitions 3'- permitting t e free passage of air beneath. This basin is provided with a tapping channel 14 where the product is to run from the basin.

The superstructure is constituted by a led e 15 resting upon angle irons 15' and pi ars 16 connected to the furnace braces and serving to support the whole. In one of the vertical we is is provided a charging aperture 5 closed by a door 6. Upon the ledges 15 rests the crown 4. Above the crown are disposed the heating chambers 7 separated by partitions 8 and closed by a top in which are rovided the feeding pockets 9 closed by t e covers 10. At the two extremities of each heating chamber are provided the electrodes 11 connected by conductors to the conducting bars 13.

The crown and the walls of the electric hearths are provided as in the construction previously described from highly refractory material being heat conductors and good electric conductors at high temperature and formed with a base of ferrite of magnesia or of ferrite of alumina. In each chamber the resistance in grains is charged as described in the first modification and in the same manner. Each chamber is filled as well as the feeding pockets whereby constant working is ensured as well as the inigpection and clearing of the heating chamers.

The disposition of the furnace represented in Figures 5 and 6 is similar to that of furnaces which have been described but the heating instead of operating through the crown alone is effected through the crown and walls combined in such manner that in this case the heating chambers entirely cover the laboratory, their section which is indicated in Figure 5 following the general form of an inverted U. The apparatus comprises a laboratory 1, a bottom 2, interior walls 3, a crown 4, exterior walls 3" and a working hole closed by a door 6. Thcfront face 3, the crown 4 and the walls of the electric hearths are made of material haxing a basis of ferrite of m nesia as previously referred to. Between t a two walls 3 and if." and above the crown 4 are disposed a seri s of heating chambers 7 separated one from the other by partitions 8. their upper tarts by a top in which is pro vided a num r of feeding chambers 9. At the lower extremities of each chamber electrodes 11 are provided connected by the con doctors 12 to the bars 13.

In each chamber the resistance material in grains is fed in the manner reviously indicated and in the same way. he material fills each chambcr and the feeding pockets and permits for the reasons above They are closed atstated a constant working and of permitting Y ular resistance mate rurnace with an oscillating crucible. As will be seen from Figures 7 and 8 the furnace su ported by the pivoting axes l7 moun on the pillars 18 comprises a crucible 19 mounted in the laborato 1. From each side of the laboratory feeding etc 9 are provided separated by rtitions 8. The resistance material feeds t ese pockets and rests upon the electrodes 11 disposed at the base of each of the heating chambers from which the extend. The oscillatin crucible is thus flanked with two In era 0 resistance material havin each general form of a U whose hranc es will be seen-in Figure 8 at 7 and 7. Thus in the different types of heated furnace according to the invention the heating chambers can be sad in the longitudinal direction as wel as transversely. In such a case numerous chambers may be provided above the crowd but only one is providedthin the uma m gachs to gispose emeasiywi t ingpoc ts. The eration of electric. resistance furnace eating radiation in the manner describedisasf m: through them-am On the current pan fithere is a transformation of the electric shot into heat. The resistance material as we as the walls of the chamber ensure this heat and take a temperature according to the quantity of heat'evolved. This is transmitted then in part by conductivity and radiation across the crown or the walls and raises the temperature of the laboratory of the furnace is well as of the substances contained therein which are to be treated, the other art being lost in the htmos here by activity and radiation from exterior walls.

If the furnace rates at a high temrature the malaria constituting the crown comes in such a case a good conductor'of electricity and it follows that a part of the current passes thro the granular resistance material and other rt thl'fllgll the crown or the walla heat thus evolved closer to the hu'nace has its transformation facilitated and thus the thermal efliciency of the furnace is increased.

What I claim is:-

1. An electric furnace, comprising a hearth the crownwall of which is formed of material which is a good conductor of heat and at high temperatures a condoctor of electricit a series 0 heating chambers above sai crown wall, granular residence material filling said heating chambers, and electrodes extendin into said chambers and contacting with said granular material.

2. An electric furnace, comprising a hearth the crown wall of which is formed of material which is a good conductor of heat and at high temperatures a good conductor of electricity, 8 series of heating chambers above said crown wall, feeding pockets forming continuations of said chambers and o ning at the top of said furnace, granulzr resistance material filling said chambers and pockets, and electrodes extending into said chambers and contacting with said granular material.

3. An electric furnace eomprisin a hearth the side and crown walls of wiich are formed of material which is a good conductor of heat and at high temperatures 'a good conductor of electricity, inverted U- shaped hcatin chambers extending, vertically along sai side walls and horizontally over the crown walls, granular resistance material filling said chambers, and electrodes extending into the lower ends of the vertical branches of the heating chambers and contacting with said granular material.

4. An electric furnace comprisin a hearth the crown and side walls of which are formed of material consietingpf ferrite of magnesia and ferrite of alumina containmg five to-ten per cent of oxide of iron, a heating chamber disposed at the outside of certain of said walls, granular resistance material filling said heating chimber, and electrodes extending into said chamber and contacting with sai granular material.

In testimony whereof have signed this cation.

MARIUS SAUVAGEON. 

